Preparative separation-purification systems using liquid chromatographs are used in pharmaceuticals or similar fields in order to collect samples to be stored in the form of a library. In a system disclosed in Patent Document 1, target components (compounds) in a sample solution are temporally separated by a liquid chromatograph. The separated target components are then introduced into respective trap columns and temporarily captured therein. Subsequently, a solvent is passed through each trap column to elute the captured component from the trap column and collect the solution containing the target component in a container. Then, the collected solution is subjected to a drying process to remove the solvent and collect the target components in solid forms.
The drying process is normally performed by heating the collected solution. This process must be performed at a moderate temperature since too high a temperature will change the quality of the target component. Accordingly, the processing time will be rather long, which may reach several hours or even up to one day for some components. This drying process consumes the longest period of time in the preparative separation-purification process. Therefore, it is essential to shorten this period.
A method for solving this problem is disclosed in Patent Documents 2-5, in which the solution is dropped in a collection container in which an amount of air, nitrogen or another kind of gas is supplied to nebulize the solution, thus promoting the vaporization of the solvent.
A normal procedure of the drying process according to the method of Patent Documents 2-5 (which is called the “gas-blowing vaporizing and drying process” in this specification) is hereinafter described by means of FIGS. 8A-8D. A preparative separation-purification system has a needle 50 having a double-tube structure which includes a solution-introducing tube 50A and a gas-introducing tube 50B which circumferentially covers the solution-introducing tube 50A, as shown in FIG. 8C. A collection container 53 held in a temperature regulation block 54 is placed below the needle 50. The collection container 53 has a container body 51 and a cap 52 which can be put on the upper opening of the container body 51. The cap 52 has two septa 52A and a doughnut-shaped cushion 52B sandwiched between the two septa 52A.
In this process, the needle 50 is lowered, penetrating the septum 50A and passing through the central hole of the cushion 52B, until its tip is inserted into the collection container 53. Along with this descending motion of the needle 50, an exhaust duct 55 is also moved downward and hermetically pressed on the cap 52 by an elastic force of the cushion 52B so as to cover the hole created in the cap 52 by the needle 50. Subsequently, a solution and a gas are respectively introduced through the solution-introducing tube 50A and the gas-introducing tube 50B into the collection container 53.
After passing through the solution-introducing tube 50A, the solution is dropped from the tip of the needle 50 inserted into the collection container 53, and simultaneously, an amount of gas is ejected from the surrounding gas-introducing tube 50B. By this stream of gas from the gas-introducing tube 50B, the solution being dropped from the solution-introducing tube 50A is sheared into fine droplets (mist) and attached to the inner wall of the collection container 53. Since the collection container 53 is preheated by the temperature regulation block 54 surrounding the container, the solvent in the fine droplets which have attached to the inner wall vaporizes, leaving only the target component (solute) in the form of powder. The gas introduced into the collection container 53 and the vaporized solvent are discharged from the gap between the hole and the needle 50, through the exhaust duct 55 to the outside of the collection container 53.